Screening apparatus



Oct. 30, 1951 w. E. KOONCE ET AL 2,572,869

SCREENING APPARATUS Filed Oct. 11, 1948 FIG. 2

ENVENTOR WILBUR Er EfiGONCE CHARLES EWORY 7 ATTORNEY I \1 Patented Oct. 30, 1951 Miss.,

assignors' to Masonite Corporation,

Laurel, Miss., a corporation of Delaware Application October 11, 1948,- Serial No. 53,966

This invention relates to an apparatus for re-' claiming fiber and more particularly to a screening apparatus for reclaiming usable fiber from the eflluent resulting from reducing the water contentof fibrous stock for making fiber-board and paper;

"In the manufacture of fiber boards, e. g., wood chips are fiberized, the fiber is refined, washed, screened on about a 65 mesh screen and then formed into a wet lap from which the board product is made. The efiiuent (material passing through this screen) contains suspended solids in about 99% Water. The amount of such solids on. a dry weight basis is approximately 16% of the fiber retained on this screen. These solids may be divided into essentially two fractions of about the same magnitude. One fraction is substantially fibrous and the other fraction is substantially non-fibrous and of a gelatinous-like nature.

Although the fibrous fraction may contain some non-fibrou material and the non-fibrous fraction may contain some fiber, the two fractions are substantially of the fibrous and non fibrous type materials.

If properly reclaimed the fibrous fraction may be used to advantage in making boards or paper by adding back to the wet lap fiber, the reclaimed fraction being about dry weight basis of the wetlap fiber retained on the 65 mesh screen: Reclaiming the fibrous fraction of this efliuent in a suitable state for adding back to the system to make boards and paper is the primary aim of this invention.

Although the need of reclaiming this fiber from the effluent has been recognized for some time, it has remained an unsolved problem of considerable difliculty until the present invention was made. Prior art apparatuses are unsuitable for this purpose because they are not adapted to recover fiber from effluent of this nature so asto obtain the fiber in a condition suitable for use. The complexity of the problem is due in part to the characteristics of the fibrous and non-fibrous tus are overcome by providing and employing r an apparatus comprising a feed supply means for the fibrous material; fiber removal means; a screen; a feed diffuser means; and sprays. 1 3

A preferred embodiment of this invention will be more fully illustrated by referring to the draw- 4 Claims. v (o1. 210-150.s)

ingslwherein identical reference. numerals are used to indicate similar parts in the figures.

Referring to the drawings generally: Figure 1 is a side elevation in partial section showing the relative combination of componen parts of the invention.

Figure 2 is a plan view of Figure 1 showing furtherdetails of the apparatus.

Referring now to the drawings in greater detail,the apparatus according to a preferred embodiment of this invention comprises a feed sup ply trough l for the fibrous material being processed; a conduit 2 fdr introducing the fibrous feed; a baffie 3 for maintaining an even fiow of the feed; a fiber removal trough 4 positioned forward and below the feed supply trough; a fixed screen 5 extending from the supply trough to the fiber removal trough, the screen presenting an inclined surface portion 5-A adjacent to the feed supply trough and substantially a horizon tal surface portion 5-13 adjacent to the fiber removal trough; a feed diffuser 6 above a part of the inclined portion 5-A of the screen in spacedapart and substantially parallel relationship therewith and extending from the feed supply trough; and sprays I positioned above the substantially horizontal portion 5-3 of the screen. Preferably the portion 5-B of the screen has a slight declination, as for example roughly two degrees.

The feed diffuser 6 is a composite unit made of a series of trough-like compartments 8 having greater depth than width and having small openings or perforations 9 in the bottom thereof. The compartments are so arranged with respect to each other and the feed supply trough as to allow the feed to overflow from the feed supply trough and fill the feed diffuser by overflowing from one compartment tov the succeeding compartment. The side walls of the compartments are imperforate or solid. Since the several compartments of the diffuser are filled with feed supply, substantially equal head pressure is obtained in the compartments and the feed supply is thus fed to trough fills,the feed flows over the entire front wall. l6 of the feed. supply. troughv and quickly.

fills the first compartment ll of the feed diffuser 6. Feed from the first compartment I I flows over the entire back wall I8 of the next compartment l9 and fills it: lnl likelamannerallstherfeed dif-f fuser compartments are=filled. The rate offeed" then is adjusted so that the overflow continues throughout the operation. The bafile 3 serves toequalize the fiow of feed to the diffuser. The-feed fiOWs through openings 9 in the bottom of the compartments and strikes the 'inclined-- portion- -A of the screen. Directional arrows A indicate the feed flow.

The feed diffuser plays an important-part in this invention. It supplies a very even and smooth flow of feed to the screen.

makes screening 'difficult; :i The feed diffuser also helps to wash the non-fibrous solids from the fiber; for which; as pointed out hereinbefore, the fib'er h'as-a'strong'afiinity. Further, the diffuseer aids in screening by increasing the feed-screen contact time in that the flow. of feed from each compartment impedes thefiow of feed 'over the substantially horizontal portion5-B of the screen where :it is' treated further. This portionof the screenflchecks'the. forward "velocity of the feed andpermits more time to further treat the feed on:: a .smaller surface of screen than" otherwise" Best results areobtained if would be possible. thisiportion .5-B ofth'e screen is sloped slightly downward from the horizontal from the inclined portion 5-'A. of the screen to the fiber removal trough '4. As the feed passes over this portion 5-B of the screen, the remaining non-fibrous solids are washed from the fiber with water from the sprays 1 Thesprays also aid in breaking up foam remaining or formed after passage from the portion of. the screen beyond the feed diffuser. However, the tendency of the feed to foam lessens as it approaches the exit end of :the screen. The refined It aids in 1 breaking up foaming of the feed, foaming being an-inherent' characteristic of. the effluent which..

fiber passes from'this substantially horizontal portion 5-13 of the screen into the trough '4; The fiber flowsfrom trough 4,"as indicated by the arrows B,f and is passed into/a storage tank back into the system Where it is used along with the usual fiber in making fiber boards.

Along the entire screen undesirable materials are being removed from the feed as indicated by the arrows C.

As many apparently widely different embodiments of this invention may be made without departing-from the -spirit and scope thereof,it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.

'We'claim:

1. Apparatus for reclaiming usable fiber from the efiiuent resulting from reducing the water content of fibrous stock for making fiber board and paper; which comprises a feed supply means; fiber removal means positioned forward and below the supply means; a fixed screen extending from the supply means to the removal means; saidscreen presenting an inclined surface portionadjacentto the supply means and a substan# tiallyi" horizontal surface portionadjacent to the removal means; a feed diffuser means above said inclined portion of the screen in spaced-apart and substantiallyxparallel relationship therewith and extending from the supply means, said diffuser means including a composite unit of a series of interconnected troughlike compartments having-:imperforate side walls and having perforations in the bottom thereof and extending across the upper part of said inclined portion of the screen;zsaid compartments having a greater depth than width and being so arranged as to allowthe' feedrto overflow from one compartment to the succeeding compartment and flow through the bottom perforations of each compartment to diffuse the feed over a substantial area of the inclined portion of the screen under substantially equal head pressure; and sprays positioned abovesaidsubstantially horizontal portion of the screen.

2. Apparatus as defined in claim 1, and-in-- which said substantially horizontal portion of the screen slopes slightly downward from the horizontal from said inclined portion-of the screen to said fiber removal means.

3. Apparatus for reclaiming usable fiber from" the effluent resulting from reducing the water? content of fibrous stock for making fiber board and paper, which comprises a feed supply means; fiber removal means positioned forward and beto the supply means and a substantially horizontal surface portion adjacent to the removal means; a feed diffuser means above a part of said 7 inclined portion of the screen in spaced-apartand substantially parallel relationship therewith and extending from the suppl means, said diffuser means including a composite unit of a series of interconnected troughlike compartments having imperforate side Walls and having perforations in the bottom thereof and extending across the upper part of said inclined portion of the screen, said compartments'having a greater depth than width and being so arranged as to allow the feed to overflow from one compart ment to the-succeeding compartment and flow through the bottom perforations of each com-' par'tment to diffuse the feed over a substantial areaof the inclined portion of the screen under, substantially equal head pressure; and sprays" positioned above said substantially horizontal portion of the screen.

4. Apparatus as defined in claim 3,and in which said substantially horizontal portion of the screen slopes slightly downward from the horizontal from said inclined portion of the screen to said fiber removal means.

WILBUR. E. KOO-NCE. CHARLES F. STORY.

REFERENCES CITED Thefollo'wing references are of record in the" file ofi'this patent:

UNITED STATES PATENTS 

